locusssssss

how to find the locus of a point P outside a circle, when the angle between the tangets frm that point to the circle is given...???

plz giv me the entire algorithm...

3 Answers

29
govind ·

Case I..if the angle b/w the tangents is 90°..then the locus of that point will be x2 + y2 = 2a2 ..if the equation of the circle is x2 + y2 = a2

Case II : If the angle b/w the tangents is 2θ ..
take the centre of the circle at origin and radius is r..
then the distance of the point from where the tangent is drawn will be r/sinθ ..by trigonometry..
so the locus will be x2 + y2 = r2 / sin2θ..

1
cute_cat ·

and if it is not at origin???

29
govind ·

If the centre is not at origin but at some general point (h,k) ..then u need to shift the origin and then the eqn will be
(x-h)2 + (y-k)2 = r2 / sin2θ

Your Answer

Close [X]